The purpose of the proposed work is to develop a digital template or atlas of the normal pediatric brain of children aged 6 to 18 years, as revealed through magnetic resonance imaging (MRI). The motivation is the spatial normalization of ensembles of MR images acquired from different children. Spatial normalization enables accurate mapping of imaged properties within the brain from any modality so long as corresponding structural MRI information is available and provides a framework for characterizing the variation of these measurements over selected population groups. In particular, the aim is to advance pediatric cognitive neuroscience research by providing a reference coordinate system which reflects the unique neuroanatomy of children. Specific aims for this proposal are as follows: 1. To develop a high-resolution, structural MRI template of the normal pediatric brain. The probabilistic template will establish a canonical space onto which neuroimaging data from children can be accurately mapped and thus compared across groups or over time. 2. To develop a corresponding normative template of pediatric brain white matter. Diffusion tensor images-a recent innovation in MRI that affords added insight into the structure of white matter regions-for the cohort will be spatially aligned and various tensor indices subsequently averaged to establish a sex- and age-defined pediatric template of normal brain white matter. 3. To evaluate the developed template via quantitative assessment of structural and white matter anomalies in children afflicted with 22q11.2 deletion syndrome. Specific hypotheses include: Children with 22q will have volumetric reductions in the inferior parietal lobes (disproportionate to reductions in whole brain volume) expressed in reductions of gray and/or white matter or some combination of these areas; and parietal white matter in 22q children will show normal diffusion and anisotropy values, but reductions in volume compromise gray matter function, or, alternatively, parietal white matter in 22q children shows abnormal diffusion and anisotropy values, thereby suggesting it as a candidate source of cognitive dysfunction.